Manufacture of electrodes



ILLINGWORTH s.l R.

April S, 1924.

MANUFACTURE OF ELECTRODES Filed Oct. 1'7. 1922v mSO fnften/E01 rendered liquid by heat,

Patented Apr. 1924.

OICE.

STEW

iNG-WORTH C r', i:

T Y ILLINGWORTE, 0F BBYNFEDWEN, RADYR, WALES, ASSIGNOB TO ONIZATION COMPANY, LIMITED, MNCEESTKM mil'Gl'nLNl).k

MANUFACTUBE OF ELECTDFS.

Application led October 17, 1922. Serial No. 595,111.

To all whom t may concern.'

Be it known that I, STEWART ROY ILLING- WORTH, a subject of the King of Great Britain, residing at Brynfedwen, Radyr, Glamorganshire, Wales, have invented new and useful Improvements in the Manufacture of Electrodes, of which the following is a specification.

This invention relates to the manufacture of electrodes, especially those adapted for use in electric furnaces.

In the production of coke from coal two factors have to be considered: (l) the resinic content and (2) the amount of volatile matter evolved at the critical stage of coking just before the mass loses its plasticity. This occurs when the resinic content is not far removed from 5% bv weight of the mass.

According to this invention I treat in the manner hereafter described coal containing not less than 5% by weightof resinic matter and in which the volatile matter evolved at the critical stage is low, that is the volatile matter must not exceed and is preferably 75%. Such coal may be natural coal or coal produced by oxidizing or blending or heating coals.

ln the present case the coals to be treated are preferablyof a high resinic contentthat is over 9% and low in ash, say about 5%; phosphorus say .1% the mass after heating to 900 centigrade. But for use in some metallurgical operations the amount of phosphorus should not exceed .05%. ln estimating the resinic content no cognizance is taken of resinic substances which decompose below 300 C. Goals suitable as regards the nature of the coal substance can be washed to produce a product of low ash content. Y

In carrying out this invention the coal as above defined is compressed, heated preferably to a temperature of 600 C.r but at least to 100 C. above the temperature of decomposition of resinic matter in the substance, then `impregnated with pitch and carbonised at 800 to 1000o C. or'upwards. the coal is `first finely crushed and is pretl erably kept under compression during the whole of the heating process.k The compressed mass may be advantageously perforated with a centralliole. 3

ln place ot heated pitch a solution of and sulphur 1% of Preferably i pitch or a solution of the heavier of the by-productsl given off during the process may be used.

The .annexed drawings show apparatus which may be employed in carrying out the manufacture according to this invention. Figure 1 is a sectionJand Figure 2 a plan of a mould and Figure 3 is a side elevation of the heating and impregnating apparatus.. Figure 4 is a diagrammatic view of a complete -apparatus for the carrying out of the process disclosed.

a is a mould having sides perforatedat b and a cover c perforated at d. The mould has in it a plate e having a lug f and two wedges g and h by means of which 'the material is held in the mould. y

Referring to Figure 3, 2' is an oven having doors j j at'each end and lc is a tank having in it a perforated plate Z pivoted at m which plate is raised and lowered by a lifting bar n. 0 is a pitch tank connected to the tank lc by a pipe p for supplying the pitch and a' return pipe g through which itch is 4run back into the tank o. The ta k is connected by a pipe 1- to a pump to evacuate the tank. A rod s may be used as indicated in Figures 1 and 2 when it is desired to form a central Vhole in the electrode.

In carrying out the invention the coal as above defined `is stamped into the mould a `and is held in the same by the plate e, lug

f and wedge g. When the mould is charged it is placed in the oven i maintained referably at a temperature of 600 C. ut at least 50 to 100 C. above the temperature of decomposition of the resinic matter. lVhen the carbonisation of the charge is complete the mould is withdrawn through the door j and the wedge h is driven into hold the mass in place. The cover is then removed :from the tank k and the perforated plate l is raised to such an angle that the mould a can be drawn down upon it. The perforated plate Z is then lowered into the tank 1c andthe cover is replaced and the tank la is evacuated through the pipe fr'. When the temperature of the tank k has cooled to about 250 C. molten pitch from the tank o is allowed to enter the tank k by the pipe p and thence into the mould a through the perforations b and d. The tank k is maintained at about 250 C. for half an hour, preferably by means of waste Hua gases from the oven i, after which the excess rola pitch is run back into the tank o through the pipe g. 'Ihe mould is then placed in an oven of the same type as the oven i and disposed on the opposite side of the tank k and is subjected to a heat of 800 to 1000 C. or upwards, after which the mould' is passed to a cooling chamber which is evacuated and preferably filled with an inert gas such as cooled flue gases.

The impregnation with pitch can be re` peated in order to get a more homogeneous product and this is particularly advisable m the case of electrodes of a cross section of over 3 square. Also in the case of lar electrodes the tank k may be advantageous y placed under pressure when the electrode 1s being impregnated.

The ovens are provided with condensing appliances so that the by-products are recovered from which pitch for use in the process may be obtained.

In place of pitch, tar or other bitumen or resinic like product, for example oil pitch, may be used, but I prefer to use a substance whlch at 900 C. will give a minimum amount of volatile matter and leave a large proportion of its weight as carbon residue without deleterious components such as sulphur.-

What I claim is 1. In the manufacture of electrodes, compressing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, heating it to a temperature at least 50y C. above the temperature of decomposition of resinic matter in the coal, impregnating the compressed coal 4with a carbonaceous substance which at 900 C. gives a minimum amount of volatile matter and leaves a large amount of carbon without deleterious components and then carbonizing.

2. In the manufacture of electrodes, compressing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, heating it to a temperature at least 50 C. above the temperature of decomposition of resinic matter in the coal, impregnating the compressed coal with pitch and then carbonizinig.'

3. In the manufacture of electrodes, compressing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, heating it to a temperature at least 50 C. above the temperature of decomposition of resinic matter inthe coal, impregnating the compressed coal with pitch rendered liquid by heat andv then carbonizing.

' 4. In the manufacture of electrodes, com pressing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage.

is low, heating it to a temperature of 600 C., impregnating the compressed coal with a carbonaceous substance which at 900 C. gives a minimum amount of volatile matter and leaves a large amount of carbon without deleterious components and then carbonizing.

5. In the manufacture of electrodes, compressing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, heating it to a temperature of 600o C., impregnating the compressed coal with pitch and then carbonizing;

6. In the manufacture of electrodes, compressing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, heating it to a temperature of 600.`C., impregnatlng the compressed coal with pitch rendered liquid by heat and then carbonzing.

7. In the manufacture of electrodes, finely crushed coal containing not less than 5%'I by weight of resinic matter and in which vthe volatile matter evolved at the critical stage is low, compressing the same about a. rod to leave a central perforation in the compressed mass, and heating it whilst under continued compression to a temperature at least 50 C. above the temperature of decomposition of resinic matter in the coal, impregnating the compressed coal with a carbonaceous substance which at 900 C. gives a minimum amount of volatile matter and leaves a large amount of carbon without deleterious components and then carbonizing.

8. In the manufacture of electrodes, finely crushed coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, compressing the same about a rod to leave a central perforation in the compressed mass, and heating it whilst under continued ,compression to a temperature at least 50 'C. above the temperature of decomposition of resinic matter in the coal, impregnating the compressed coal with pitch and then carbonizing.

9. In the manufacture of electrodes, finely crushing coal containing not less than 5% by weight of resinic matter and in which the volatile matter evolved at the critical stage is low, compressing the same and Iheating it whilst under continued compression'to a temperature at least 50 C. above the temperature of decomposition of resinic matter in the coal, impregnating the compressed coal with a carbonaceous substance which at 900 C. gives a minimum amount of volatile matter and leaves alarge amount of carbon, without deleterious components and then carbonizing.

10. In the manufacture lof electrodes, line- 1y crushing eo by weight of meeao al containing not less than 5% resinic matter and in which the volatile matter evolved at the critical stage is 10W,

compressing the same, and

heating it whilst under continued compression to a temperature at least 50 C. above the temperature of decomposition of resinic matter in the coal, imregnating the compressed conl with pito andthen carbonizing.

In testimony that I claim the foregoing as my invention I have signed my name this 6th day of October, 1922.

STEWART ROY ILLINGWORTH. 

